Varicose veins are dilated and tortuous veins, typically superficial veins of the leg. Varicosity is generally caused by an absence or weakness of valves that normally prevent the backward flow of blood away from the heart, or by weaknesses in the vein walls that cause blood to pool.
Techniques for treating varicose veins include surgery and sclerotherapy. Sclerotherapy is the injection directly into the vein of a solution that irritates the lining of the vein, causing it to swell and the blood to clot. Surgical techniques include making two incisions in the vein, one at the ankle and one at the groin. An elongate stripper instrument is then inserted through the ankle incision and passed through the vein to the groin, where a cup is attached to the distal end of the stripper. The stripper is then pulled down the leg, causing the cup to tear out the vein. Newer surgical techniques include damaging an inner endothelial surface of the vein with laser, electric, or radiofrequency (RF) energy.
U.S. Pat. Nos. 6,689,126 and 6,398,780 to Farley et al., which are incorporated herein by reference, describe a catheter including a plurality of primary leads for delivering energy for ligating a hollow anatomical structure. High frequency energy is applied from the leads to create a heating effect in the surrounding tissue of the anatomical structure. Where the hollow anatomical structure is a vein, energy is applied until the diameter of the vein is reduced to the point where the vein is occluded. In one embodiment, a balloon is inflated to occlude the structure before the application of energy. Where the structure is a vein, the inflated balloon obstructs blood flow and facilitates the infusion of saline, medication, or a high-impedance fluid to the vein in order to reduce the occurrence of coagulation and to improve the heating of the vein by the catheter.
U.S. Pat. No. 6,322,559 to Daulton et al., which is incorporated herein by reference, describes an electrode catheter including a coil located at its distal working end. The coil produces an RF field which heats the surrounding venous tissue and causes a reduction in the diameter of the vein. In some embodiments, the catheter includes a balloon that is inflated to engage the coil and occlude the vein. As RF energy is applied, the vein becomes heated and begins to shrink. Occluding the blood flow in the vein with the inflated balloon is described as being able to reduce the effect of blood flow carrying heat away from the treatment site in contact with the electrodes, and to shield blood from heat during treatment, to avoid thrombus formation.
U.S. Pat. Nos. 6,179,832 and 6,682,526 to Jones et al., which are incorporated herein by reference, describe a catheter including a first plurality of expandable leads and a second plurality of expandable leads that are separate and longitudinally spaced-apart from the first plurality. The leads deliver radio frequency (RF) energy, microwave energy, or thermal energy to a hollow anatomical structure, such as vein, fallopian tube, hemorrhoid, or esophageal varix, in order to ligate the structure.
U.S. Pat. No. 6,033,398 to Farley et al., which is incorporated herein by reference, describes a catheter adapted to introduce electrodes into a vein for a minimally invasive treatment of venous insufficiency by the application of energy to cause selective heating of the vein. The catheter is positioned within the vein to be treated, and the electrodes on the catheter are moved toward one side of the vein. RF energy is applied in a directional manner from the electrodes at the working end of the catheter to cause localized heating and corresponding shrinkage of the adjacent venous tissue, which may include commissures, leaflets and ostia. Alternatively, the electrodes can be wires located along or embedded in the surface of the working end of the catheter, in which case the wires generate heat when suitable energy is applied. For example, the wires may be formed of a resistive material and may heat up when electricity is conducted through them. Fluoroscopy or ultrasound may be used to detect shrinkage of the vein. After treating one section of the vein, the catheter can be repositioned to place the electrodes to treat different sections of the vein until, as described, all desired venous valves are repaired and rendered functionally competent.
U.S. Pat. No. 6,071,277 to Farley et al., which is incorporated herein by reference, describes a catheter adapted to deliver an electrode within a hollow anatomical structure for a minimally invasive treatment which reduces the size of the structure. The catheter is introduced and positioned within a section of the hollow anatomical structure to be treated. The electrode radiates high frequency energy, and the surrounding tissue of the hollow anatomical structure becomes heated and begins to shrink. The catheter includes a controllable member for limiting the amount of shrinkage. The temperature of the surrounding hollow anatomical structure can be monitored while the electrode radiates high frequency energy. After treating one section of the hollow anatomical structure, the catheter and electrodes can be repositioned intraluminally to treat different sections of the hollow anatomical structure.
U.S. Pat. No. 6,402,745 to Wilk, which is incorporated herein by reference, describes an intravenous surgical instrument for treating a blood vessel, such as a varicose vein. The instrument comprises an inner shaft or post and an outer sheath. At a distal end of the inner post a spring-tail or whip-like electrode is disposed substantially in a sagittal plane, or one perpendicular to a longitudinal axis of the shaft. Following insertion into the vessel, the distal end of the shaft is protruded from the sheath, and the sheath, post, and electrode are simultaneously withdrawn from the vessel, with a relative rotatory motion being imparted to the electrode. A current flow is preferably simultaneously imposed across the electrode into an inner surface of the surrounding vessel, facilitating damaging of the vessel inner surface and collapse of the vessel.
U.S. Pat. No. 4,869,248 to Narula, which is incorporated herein by reference, describes a thermal ablation catheter for microtransection or macrotransection of conduction paths within the heart. The catheter includes a resistive heating element at its distal end for highly localized treatment. The heating element includes a resistive wire loop connected to an external power source, and has a prescribed shape to insure that the wire loop is approximately perpendicular to the surface to be treated.
U.S. Pat. No. 6,712,806 to St. Germain et al., which is incorporated herein by reference, describes a method for increasing cerebral blood flow. A catheter is inserted into the descending aorta, the catheter having a proximal region, a distal region, and at least one expandable member mounted on the distal region. The expandable member is positioned downstream from the takeoff of the brachiocephalic artery. The expandable member is expanded to at least partially obstruct blood flow in the aorta. The expandable member is then cycled between greater and lesser obstruction of blood flow. Renal ischemia and lower limb ischemia is described as being avoided in this manner.
U.S. Pat. No. 6,712,804 to Roue et al., which is incorporated herein by reference, describes a closure catheter, for closing a tissue opening such as an atrial septal defect, patent foramen ovale, or the left atrial appendage of the heart. The closure catheter carries a plurality of tissue anchors, which may be deployed into tissue surrounding the opening, and used to draw the opening closed.
U.S. Pat. No. 6,451,007 to Koop et al., which is incorporated herein by reference, describes techniques for selective heating of subsurface structures in material such as tissue, including a cooling device for thermally quenching or removing heat from the top surface of tissue during or just after delivering pulsed energy to target or subsurface structures or tissue. An embodiment uses dynamic cooling, to quench the thermal energy conducted from the targeted structure into surrounding tissue.
U.S. Pat. No. 6,712,815 to Sampson et al., which is incorporated herein by reference, describes ablation techniques for closing veins, for treatment of venous insufficiency disease. The apparatus includes a catheter proportioned for insertion into a vein, a pair of inflatable balloons spaced apart on the catheter body, and an ablation electrode array disposed between the balloons. The catheter is introduced into the vein to be treated and the balloons are distended. Blood is flushed and aspirated from the site between the balloons. RF power is applied to the electrode array, causing scarring of the vessel walls and eventual sealing of the vein.
U.S. Pat. No. 6,676,657 to Wood, which is incorporated herein by reference, describes techniques for occluding the lumen of a hollow organ by delivering radiofrequency energy to the inner wall of the organ. Radiofrequency electrodes are described that expand, in a deployed condition, to contact the walls of the organ. In some embodiments, the electrodes substantially conform to the inner wall to enhance therapeutic contact. Methods are also disclosed for using these electrodes to totally or partially occlude a lumen, or to remove or reduce a total or partial occlusion of a lumen. For some applications, the electrodes include an expandable distal end that is retracted, or collapsed into a compact configuration, in the non-deployed position and is expanded in the deployed position. The expandable distal end can assume the form of a plurality of struts that extend longitudinally with respect to the conductive member, and the struts are attached to the conductive member such that longitudinal movement of the conductive member moves the struts between the retracted and expanded positions. For example, the struts are attached at a first end to the conductive member and are fixed at a second end around the conductive member, such that longitudinal movement of the conductive member (for example retraction of the conductive member toward a sheath) forces the struts into the expanded position. The device can include a sheath around the catheter, to which the proximal end of the struts is attached. As the distal end of the conductive member is pulled toward the sheath, the struts are compressed and expand to the deployed position in contact with the wall of the lumen.
U.S. Pat. No. 6,772,013 to Ingle et al., which is incorporated herein by reference, describes techniques for treating urinary incontinence generally relying on energy delivered to a patient's own pelvic support tissue to selectively contract or shrink at least a portion of that pelvic support tissue so as to reposition the bladder. Techniques are described for applying gentle resistive heating of these and other tissues to cause them to contract without imposing significant injury on the surrounding tissue structures.
U.S. Pat. No. 6,768,086 to Sullivan et al., which is incorporated herein by reference, describes a warming blanket having a temperature sensing element for sensing the temperature of the warming blanket.
US Patent Application Publication 2004/0199155 to Mollenauer, which is incorporated herein by reference, describes techniques for the treatment of various incompetent valves and sphincters throughout the body. The catheters provide for location of a heating element or other tissue necrosing tool in the lumen of the vessel controlled by the valve, at or near the base of the valve (but not on the valve itself). Additionally, the catheters include balloons for locating and anchoring the distal section of the catheter within the lumen, such that the heating element is positioned near the base of the valve, in contact with lumenal tissue at the base of the valve. The catheters also include suction ports on the distal end of the catheter which can be operated to size or draw down the vessel to the diameter of the catheter, so that the vessel walls are in contact with the heating elements. The heating elements comprise resistive heating elements, electrodes, RF electrodes, ultrasonic heat sources, LEDs and other light or laser sources, or other suitable heating mechanisms. Where the heating elements are resistive heating elements, the electrical wires comprise a ground wire and a hot wire, and, as described, while a minor amount of current may pass through the body to ground, the bulk heating of the venous tissue is caused by conductive heating from the heating elements which are in turn heated due to resistance of the elements and the passage of current through the elements. Appropriate materials for the resistive heating elements include nichrome and nickel-titanium alloys such as nitinol.
US Patent Application Publication 2004/0010298 to Altshuler et al., which is incorporated herein by reference, describes techniques for selectively heating blood vessels in a patient's skin to effect a desired dermatological (medical or cosmetic) treatment. For shallow vessels, particularly plexus vessels and superficial vessels/veins, radiation is applied to the vessels involved in the treatment which includes substantial radiation in a blue band of approximately 380-450 nm. The treatment may be enhanced by applying pressure and/or cooling to the patient's skin which, among other things, removes blood from blood vessels above blood vessels for which treatment is desired.
US Patent Application Publication 2003/0109869 to Shadduck, which is incorporated herein by reference, describes a medical instrument that utilizes electrical energy delivery between first and second opposing polarity electrodes in an interior bore of a working end to cause vaporization of an inflowing fluid media. The vaporization and expansion of the fluid media creates pressure gradients in the working end that causes heated vapor to propagate distally from the working end. The propagation or jetting of the vapor media is used to controllably cause thermal effects in endoluminal environments. The instrument and method can be used to shrink and occlude blood vessels in a treatment for varicose veins. US Patent Application Publications 2004/0199226 and 2004/0068306 to Shadduck, which are incorporated herein by reference, describe similar techniques for treating tissue with heat.
US Patent Application Publication 2003/0120256 to Lary et al., which is incorporated herein by reference, describes apparatus for sclerosing the wall of a varicose vein, which includes an inner tube having an expandable balloon at its distal end, an intermediate tube slidably disposed over the inner tube and having a fluid outlet at its distal end and a plunger at its proximal end, and an outer tube through which the plunger is movable. Methods of using the apparatus include deploying the inner and intermediate tubes in the vessel to be sclerosed, inflating the balloon, filling the outer tube with sclerosing agent and moving the plunger from the distal end of the outer tube toward the proximal end.
US Patent Application Publication 2004/0092913 to Hennings et al., which is incorporated herein by reference, describes techniques for treating varicose veins or the greater saphenous vein. The techniques include the use of infrared laser radiation in the region of 1.2 to 1.8 um in a manner from inside the vessel such that the endothelial cells of the vessel wall are damaged, collagen fibers in the vessel wall are heated to the point where they permanently contract, and the vessel is occluded and ultimately resorbed. The device includes a laser delivered via a fiber optic catheter that may have frosted or diffusing fiber tips. A motorized pull back device is used, and a thermal sensor may be used to help control the power required to maintain the proper treatment temperature. A controlled cooling system is described which allows a predetermined amount of cryogenic fluid to be dispensed from an on-board fluid reservoir or from an external/line source. In an embodiment, the cooling device is computer controlled, to provide spurts or squirts of cryogenic fluid at a predetermined rate or for a predetermined duration.
US Patent Application Publication 2002/0072761 to Abrams et al., which is incorporated herein by reference, describes surgical techniques for achieving a desired configuration of one or more anatomical structures by suction or inflation, and then by optionally deploying a stabilizing or fastening agent or holding device, for example a helical staple, to stabilize the anatomical structure in the desired configuration. Aspects of the invention can be used in the treatment of incontinence, coronary artery blockage, tubal ligation, vasectomy, treatment of morbid obesity, and treatment of varicose veins. For some applications, a wire is deployed within the lumen of the fallopian tube or other anatomical structure, to sufficiently damage the tissue prior to placement of the helical staple or other stabilizing or fastening agent. Tissue damage in this manner is described as tending to promote more rapid tissue growth, better ensuring closure of the anatomical structure. For some applications, the wire is a resistive wire that is heated and thus causes thermal damage. Alternatively or additionally, the wire is an abrasive wire that damages the tissue by direct abrasive contact.
PCT Publication WO 04/071612 to Slater et al., which is incorporated herein by reference, describes techniques for treating the interior of a blood vessel, including a variety of catheter designs, methods and apparatus for occluding a blood vessel, including an inflatable occlusion balloon.